Photocatalytic Activity of Titanium Dioxide Nanoparticles (TiO2) on the Physiological and Phytochemical Properties of Stevia [Stevia rebaudiana (Bertoni) Bertoni]

This study investigated the photocatalytic effect of titanium dioxide nanoparticles on some physiological and phytochemical properties of stevia plant. Stevia plant was treated with eight concentrations of titanium dioxide nanoparticles (0, 20, 40, 60, 80, 100, 200 and 400 µL/L). After 3 weeks of plants treatment, samples were collected for analysis of chlorophyll, PAL enzyme activity, total phenol and flavonoid content. Also extraction of plant for assessment of steviosides and rebaudiosides glycosides by HPLC was performed. The results showed that treatment of titanium dioxide nanoparticles at 400 µL/Lconcentration had the highest and at control had the lowest effect on chlorophyll content of leaves, total phenol, total flavonoid and Phenylalanine ammonia lyase enzyme activity. Glycoside content showed that treatment of nanoparticle at 200 µL/L concentration had the highest and control concentration had lowest effect on stevioside content. Rebaudiosides content showed that, nanoparticle at 400 µL/L had highest effect and at 20 and 40 µL/L had lowest effect on rebaudioside A and B content. But, nanoparticle at 80 µL/L had maximum effect, and at 20 and 40 µL/L had lowest effect on rebaudioside C and F content. It was concluded that varied concentration of nanoparticles has different effect on glycosides content that this results could apply for further technologies in agriculture industry.